This invention relates to a rotary mower head adapted for carrying a plurality of monofilament line cutters, and more particularly concerns a monofilament line cutter having certain universal fit features which adapt the head for replacing conventional cutting blades.
Conventional rotary mowers carry an elongated blade which is centrally mounted on a shaft rotatably driven by an engine during the cutting operation. To assist in preventing rotation of the blade with respect to the shaft, certain conventional rotary mowers incorporate a hub having keys positioned at preselected locations which engage openings within the blade on either side of the bore through which the mounting shaft extends. The spacing of the keys from each other and from the central portion of the shaft varys depending on the particular manufacturer of the mower.
Certain problems concommitant with the operation of rotary mowers are well known in the art. For example, if an operator comes into contact with the rotating blade during the cutting operations, serious injury is likely to be incurred. Such injurys are normally occasioned during the starting operation or while mowing, as when an operator or bystander inadvertantly moves a portion of his body, such as his foot, under the mower housing and into contact with the rotating blade. Moreover, rotary mowers tend to throw projectiles such as rocks, sticks, or other items at rest in the vegetation to be cut, from the discharge section of the mower housing. These projectiles often travel at a high velocity and may strike a bystander, or the operator, causing severe injury such as the loss of an eye.
In order to maintain a rotary mower in satisfactory operating condition, it is necessary that the end portions of the cutting blade be periodically sharpened. To this end, an operator must be removed the blade from the mounting shaft, and hone the end portions of the blade to a cutting edge as with a file. After a period of time, and sucessive sharpenings, the blade can become unbalanced due to the unequal removal of stock from one end portion thereof. An unbalanced blade may cause substantial vibration in the mower and/or unnoticed and accelerated deterioration of the engine.
Accordingly, it is an object of the present invention to provide an improved mower head which can be mounted on conventional rotary cutting mowers to replace the existing blade.
Another object of the invention is to provide a rotary cutting blade replacement which can be readily installed and which can be safely operated.
A further object of the invention is to provide a mower head incorporating monofilament lines which can be readily and inexpensively replaced.
Still another object of the invention is to provide a mower head which generates air currents in a vertical direction to stand the vegetation up during the cutting operation to assist in assuring an even cut.
Yet, another object of the invention is to provide a system for mounting the monofilament lines which reduces the stress forces applied to the line during the cutting operation thereby increasing the useful life of the lines.